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Fatigue-damage prediction for ship and offshore structures under wide-banded non-Gaussian random loadings part I: Approximation of cycle distribution in wide-banded gaussian random processes
Abstract Ships and offshore structures are exposed to various cyclic loads such as winds, waves and currents in their lifetime. These loads can result in fatigue failures at hot spots, and so to prevent such failures, accurate estimates of the fatigue life of hot spots should be performed in the design stage. The cycle distribution indicative of the probability distribution of cycles is an important factor in estimation of fatigue damage to mechanical systems in frequency-domain methods. It depends on not only the counting method but also the statistical properties of random processes. Many studies deriving both theoretical and approximate models of rainflow-counted cycle distributions in wide-banded non-Gaussian processes have been conducted. However, some of the existing models require multi-dimensional integrations that require much computational time or yield inaccurate representations of rainflow-cycle distributions. Therefore, a new model providing accurate cycle distributions is needed for fatigue analysis of offshore structures under wide-banded non-Gaussian random loadings. This paper consists of two parts: Part I is devoted to the development of a new approximate model of the joint probability distribution (JPD) of mean and amplitude of rainflow-counted cycles in wide-banded Gaussian random processes. Nonlinear regression analysis is performed to approximate the conditional probability density function (PDF) of the cycle mean value. The accuracy of the proposed model was verified through two numerical examples. This probabilistic model derived in Gaussian random processes could be transformed to the corresponding non-Gaussian processes through a non-linear transformation technique. In the forthcoming Part II, the accuracy of the proposed model for fatigue-damage assessment of offshore structures under non-Gaussian random loading will be discussed.
Fatigue-damage prediction for ship and offshore structures under wide-banded non-Gaussian random loadings part I: Approximation of cycle distribution in wide-banded gaussian random processes
Abstract Ships and offshore structures are exposed to various cyclic loads such as winds, waves and currents in their lifetime. These loads can result in fatigue failures at hot spots, and so to prevent such failures, accurate estimates of the fatigue life of hot spots should be performed in the design stage. The cycle distribution indicative of the probability distribution of cycles is an important factor in estimation of fatigue damage to mechanical systems in frequency-domain methods. It depends on not only the counting method but also the statistical properties of random processes. Many studies deriving both theoretical and approximate models of rainflow-counted cycle distributions in wide-banded non-Gaussian processes have been conducted. However, some of the existing models require multi-dimensional integrations that require much computational time or yield inaccurate representations of rainflow-cycle distributions. Therefore, a new model providing accurate cycle distributions is needed for fatigue analysis of offshore structures under wide-banded non-Gaussian random loadings. This paper consists of two parts: Part I is devoted to the development of a new approximate model of the joint probability distribution (JPD) of mean and amplitude of rainflow-counted cycles in wide-banded Gaussian random processes. Nonlinear regression analysis is performed to approximate the conditional probability density function (PDF) of the cycle mean value. The accuracy of the proposed model was verified through two numerical examples. This probabilistic model derived in Gaussian random processes could be transformed to the corresponding non-Gaussian processes through a non-linear transformation technique. In the forthcoming Part II, the accuracy of the proposed model for fatigue-damage assessment of offshore structures under non-Gaussian random loading will be discussed.
Fatigue-damage prediction for ship and offshore structures under wide-banded non-Gaussian random loadings part I: Approximation of cycle distribution in wide-banded gaussian random processes
Kim, Hyeon-jin (author) / Jang, Beom-Seon (author) / Kim, Jeong Du (author)
Applied Ocean Research ; 101
2020-07-13
Article (Journal)
Electronic Resource
English
Fatigue life assessment in non-Gaussian random loadings
| British Library Online Contents | 2006